Many industries require containers for particulate, semisolid, or liquid products. Such containers must be sturdy and inexpensive. These requirements are particularly acute within the fast-food industry for beverage containers, as well as in the dairy products industry. Because of the economies, such containers must be quite inexpensive and must incorporate closures, e.g., lids, to prevent spillage of their contents. Because fast-food goods must be prepared fast, it is important that when a beverage is filled, it can be closed quickly and easily by a relatively unskilled labor force. In addition, because many such beverages are transferred in mechanically unstable environments, e.g., automobiles, cup holders, and laps, the containers must be secured against spillage and leakage.
The current state of the art, in use across the take-away food industry, uses a two-part container, consisting of a waxed paper or plastic cup, together with a separate, usually plastic, lid. The lid clips into place over a rolled rim on the cup. The lid may also be perforated by one or more holes to allow limited access to the fluid (e.g., a slit in the rim of a coffee cup), or to allow insertion of a straw.
Using a separate plastic lid presents several undesirable aspects. First, two different vendors and supply streams must be supported, adding to operational cost. Second, the lids themselves are inconvenient to work with, often sticking together, or getting dropped and leading to excess wastage. Third, plastic lids are perceived as less environmentally desirable than, e.g., paper cups. Fourth, a plastic lid can easily be imperfectly attached, leading to a phenomenon where the lid is popped off by moderate pressure placed on the cup. Fifth, if the cup is inadvertently jostled or knocked over, the lid can pop off, spilling the entire contents of the cup.
These drawbacks lead to higher operating costs and reluctance on the part of consumers to purchases beverages in such cups in unstable environments such as drive-through ordering environments.
It would lead to significant benefits such as cost reduction if the separate lid could be eliminated and the closure of the container obtained by modifying the cup itself. There would be less inventory, less wastage, and the closure would now be made of the same material as the cup, which could be paper or an even more environmentally benign material.
Furthermore, it would be a benefit if an integrated closure could be realized that provided better resistance to undesired leakage and/or opening than the traditional plastic lid.
It would also be a benefit if the integrated closure could be quickly and easily closed by a relatively unskilled employee, and if the integrated closure could provide a positive indication that closure had been achieved.
An integral closure may be realized by adding a series of folds to the container which, when activated, create the closure from the same material as the rest of the container.
A fold may be characterized as being either a mountain fold, in which the activated fold is convex toward the outside of the container, or a valley fold, in which the activated fold is concave toward the outside of the container (and thus is convex toward the interior of the container).
In the prior art, U.S. Pat. No. 4,712,725 ('725 hereafter) discloses a container with an integral fold-in closure lid, as shown in FIGS. 1(a)-(c). FIG. 1(a) shows a side view of the container; FIG. 1(b) shows a top view of the container; and FIG. 1(c) shows a plan view of the blank from which the container is fabricated. In this patent, the top edge of the cup is divided by a series of triangular folds into a large number of triangular panels. The folds consist of two types: “mountain” folds, which are peaked toward the observer, and “valley” folds, which are peaked away from the observer. These panels are folded down around the lid so that all edges meet in the middle of the cup to effect a closure. The patent discloses that any number of segments may be used, but a preferred embodiment uses twelve segments.
The container of '725 offers the advantage of an integral closure, but it also has several disadvantages. The relatively large number of segments means that many different segments must be simultaneously manipulated. Furthermore, the locking mechanism is not particularly strong, and empirical tests reveal that a cup fabricated according to any of the disclosed embodiments are relatively susceptible to having the lid pop open under relatively minor stresses. It should be noted that among all of the variations described and disclosed in '725, they all share the property that the valley folds extending from the rim of the cup terminate in the very center of the cup.
Another patent in the prior art, U.S. Pat. No. 5,676,306 ('306 hereafter) also discloses a container with an integral fold-in closure lid. In this patent, the top edge of the cup is divided by series of triangular folds into a large number of triangular and quadrilateral panels. These panels are formed in concert with a recessed rim composed of two parallel closely-spaced creases running around the rim of the cup. When the panels are folded down, they form a closure of the top of the cup. The pattern of the creases around the rim is similar to the pattern of the creases in '725, but the locations, angles, and fold angles of the creases differ from those in '725 so that while the flanges formed by the mountain folds in '725 stand straight up and down, the flanges formed by the mountain folds in '306 run sideways and overlap one another. The closure of '306 and closure of '725 share the important property that the valley folds run from the rim of the cup into the very center of the closure where the paper terminates. No valley fold extends beyond the center when the closure is engaged, and in fact no paper extends beyond the center in '306 except for a tab provided for re-opening the container; the tab plays no role in holding the closure shut.
The container in '306 shares a disadvantage with '725, that it is still relatively weak and lateral stresses easily dislodge the closure.
Furthermore, the preferred embodiments of the invention of '306 utilizes six or twelve flanges, so that when closing the cup, all six flanges must be simultaneously manipulated, thus requiring a skilled operator to quickly effect closure of the container. This closure is made particularly difficult in that each pair of adjacent mountain and valley folds are only weakly coupled to one another, so that individual folds can, and in fact, must be operated simultaneously by the user, requiring considerable physical dexterity.
Another patent in the prior art, GB Patent No. 2,380,397 ('397 hereafter) discloses a container with an integral fold-in closure lid. In this patent, the top edge of the cup is divided by a series of triangular folds into a large number of triangular and quadrilateral panels. When the panels are folded down, their edges meet in the center of the cup and they form a closure of the top of the cup. The pattern of the creases around the rim is similar to the pattern of the creases in '725, but all folds are straight so that the top of the cup is forced into a polygonal, rather than conical cross section.
'397 discloses several different embodiments in which the parity of the creases differs from one embodiment to the next. For example, in their FIG. 10-11, the vertical folds are valley folds and the diagonal folds are mountain folds, whereas in their FIG. 13, the vertical folds are mountain folds and the diagonal folds are valley folds. Common to all embodiments disclosed in '397 that have vertical and diagonals folds is the property that the vertical folds meet and terminate in the center of the cup. This property results in a weak and easily dislodged closure, as it does in '725 and '306.
It would be desirable to use a different folding pattern from those disclosed in the aforementioned containers. There are several patterns within the origami literature that are somewhat similar to the folding patterns disclosed in this prior art, which can be applied to a polygonal or cylindrical shape to effect a closure.
In the book, “Rittai Origami,” written by Shuzo Fujimoto and published in 1976, there is disclosed several polygonal decorative forms in which the upper end of a roughly cylindrical faceted form is patterned with a series of vertical mountain folds and diagonal valley folds. See FIGS. 41-1, 41-2, 42-1, 42-3, 43-1, and 43-2. When the folds are activated, the top of the shape twists to form a flat closure. The dimensions of the shape and fold angles are chosen so that the valley folds extend well beyond the center of the folded shape, in contrast to the aforementioned prior art. However, this form is presented as a decorative shape, rather than a container. Also, the angles are chosen so that the top lies flat with no recess, so that there is no tensional force keeping the twist in place.
In the book, “Ichimai Ori No Haku”, written by Tomoko Fuse and published in 1992, there are disclosed a multiplicity of two-piece boxes in which the lids of said boxes are folded by creating a pattern of vertical mountain and diagonal valley folds that, when activated, twist to form a flat structure. While the pattern is superficially similar to the folding patterns already presented and the pattern of the present invention, the twist fold is used merely as a decorative element and is not intended to be opened and closed; instead, the container on which it is used is opened by merely lifting off the separate piece comprising the lid.
In the book “Origami in Action,” written by the inventor and published in 1997, there is also disclosed a cylindrical form in which vertical mountain folds and diagonal valleys are created so that when all folds are activated, the top of the form twists to form a flat closure in which the valley folds extend well beyond the center of the twist. However, this pattern is again used as a decorative form rather than as a functional element in a container.
It is the object to provide a container with an integrated folding closure that provides a more secure lock than that provided by the prior art.
It is a further object to provide a method for closing the container that requires minimal manipulation, so that a skilled operator can quickly execute the closure in a secure manner.
It is a further object to provide means for decoration and/or advertisement on the finished lid.